1. Field of the Invention
The present invention relates to an image recording apparatus for recording an image on a recording medium by scanning a surface of the recording medium with a light beam.
2. Description of the Background Art
An image recording apparatus for recording an image on a surface of a printing plate by scanning the surface of the printing plate with a light beam has conventionally been known. For example, an image recording apparatus for recording an image on a surface of a printing plate for use in flexographic printing and letterpress printing has been known. The surface of the printing plate for use in flexographic printing and letterpress printing is made of a photosensitive resin. When irradiated with a light beam, the surface of the printing plate becomes uneven, whereby an image is recorded on the printing plate.
For the recording of an image on such a printing plate with reliability, it is desirable to increase the energy given from the light beam to a recording location on the printing plate. For the increase in the energy given from the light beam, National Publication of Translation No. 11-500962 (1999) discloses the technique of irradiating a printing plate with a plurality of laser light beams brought together on the same optical axis, and Japanese Patent No. 3556204 discloses the technique of recording at the same position on a printing plate sequentially with a plurality of beams.
The technique disclosed in National Publication of Translation No. 11-500962, however, requires the provision of an optical system for bringing the plurality of laser light beams together to present a problem in that mechanical parts including the optical system have a complicated structure. The technique disclosed in Japanese Patent No. 3556204 presents the problem of significant decrease in image recording speed because all of the beams sequentially impinge upon the same position on the printing plate. Increasing the speed of rotation of a recording drum and the speed of feed of a recording head can improve the image recording speed. However, there are definite limits to the increase in the speed of operation of systems for driving the recording drum, the recording head and the like.